Electronic circuit cards, including non-volatile memory cards, have been commercially implemented according to a number of well-known standards. Memory cards are used with personal computers, cellular telephones, personal digital assistants (PDAs), digital still cameras, digital movie cameras, portable audio players and other host electronic devices for the storage of large amounts of data. Such cards usually contain a re-programmable non-volatile semiconductor memory cell array along with a controller that controls operation of the memory cell array and interfaces with a host to which the card connected. Several of the same type of card may be interchanged in a host card slot designed to accept that type of card. However, the development of the many electronic card standards has created different types of cards that are incompatible with each other in various degrees. A card made according to one standard is usually not useable with a host designed to operate with a card of another standard.
A number of standards exist for memory cards, which continue to evolve as new standards are introduced. For example, one generation of memory cards may introduce a higher speed bus than a preceding generation. For practicality in the market, it is desirable to optimize the user experience with minimal frustration along with an effort to minimize the host and card manufacturer's risk by keeping backward compatibility with older protocols at various levels.